Lock



FIG. 1 is a side elevational view of a lock showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view opposite to FIG. 1;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a perspective view thereof.

The broken lines, which define the boundary of the claimed design form no part thereof.

The broken lines environmental are for illustrative purpose only and form no part of the claimed design. 

The ornamental design for a lock, as shown and described. 